Longer follow-up must show lasting boxcar smoothing at three to six months, measured with validated scar scores. The January 2026 antioxidant trial showed faster early healing, but it stopped at 14 days.
Fractional CO2 laser drills tiny columns into scar tissue to trigger remodeling. Boxcar scars are a specific shape that needs its own proof. Antioxidant serum here means CE Ferulic with vitamin C, vitamin E and ferulic acid.
Medical information disclaimer: This article is for general educational purposes only and does not provide medical advice, diagnosis, or treatment. Always consult a physician or other qualified health professional about symptoms, medications, tests, or treatment decisions.
Table of Contents
- What the January 2026 serum trial measured
- Why boxcar scars need their own proof
- Why two weeks cannot show pigment safety
- What a 3- to 6-month follow-up must report
What the January 2026 serum trial measured
A randomized, investigator-blinded, split-face trial enrolled Chinese adults aged 18 to 50 with moderate-to-severe atrophic acne scars. One cheek received CE Ferulic serum and the other received normal saline right after ablative fractional CO2 laser.
Treatment continued for 14 days, according to the Journal of Cosmetic Dermatology via PubMed Central in the split-face trial report. The serum side healed faster during the two-week window. It showed lower redness and melanin readings plus better-preserved hydration and barrier function than saline, the same report found.
Why boxcar scars need their own proof
Boxcar scars are round or oval U-shaped depressions 1.5 to 4.0 mm wide with sharp vertical edges. Shallow boxcar scars respond favorably to fractional laser resurfacing. Deeper boxcar scars often require combination approaches such as subcision or filler, according to the SAGE Journals scar-management review in the scar-management review.
A split-face comparison in the Indian Journal of Postgraduate Dermatology focused on boxcar scars. It reported about 66 percent improvement with fractional CO2 laser versus about 54 percent with microneedling. That result keeps CO2 relevant for boxcar-predominant scarring, but it does not prove added serum benefit.
Why two weeks cannot show pigment safety
Redness and brown marks keep changing for months after CO2. One Asian-skin study found post-inflammatory hyperpigmentation in 6 of 25 patients after a single fractional CO2 treatment. Five cases faded by 3 months, according to the 10,600-nm fractional CO2 study in Asian skin in the Asian-skin fractional CO2 study.
Erythema means lingering redness. It can take up to six months to fade in reviews. A 14-day check therefore misses late fading, stubborn spots, and recurrence.
What a 3- to 6-month follow-up must report
The 14-day antioxidant trial measured early healing, redness, pigment and hydration. Durable boxcar remodeling, recurrence, persistent hyperpigmentation and validated scar-grade change were not measured. The Journal of Cosmetic Dermatology via Wiley flags that short follow-up as the key limit.
Longer follow-up must report boxcar-specific validated scores at three to six months. One model is Quantitative Global Scarring Grading System scoring at 3 to 6 months. Poly-L-lactic acid plus CO2 laser groups used that 6-month window, according to the PubMed-indexed acne-scar trial record in the acne-scar trial record. Ask for these boxcar items separately, not as one overall scar average: Bring dated photos and ask how your clinic tracks boxcar scores and pigment at three and six months.
- boxcar-only score change at 3 and 6 months
- persistent redness and brown marks by count
- need for subcision, filler or repeat laser
- hydration and barrier only as support, not proof of smoothing
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